Neural and Hormal influences of Agression

Question 1

The limbic system
(Neural influences)
AO1

Answer 1

coordinations behaviours that satify motivational and emotional urges such as agression and fear. Two key structures in the limbic system, that are associated with agression are the amygdala and the hippocampus.

Question 2

The amygdala

AO1

Answer 2

Is responsible for evaluating the emotional importance of sensory information and prompting an appropraite response. If certain areas of the amygdala are stimulated, an animal responds with agression.

Question 3

Th hippocampus

Answer 3

Is involved with the formation of long-term memories, allowing an animal to compare the conditions of a current threat with similar past experiences. Impaired hippocampal function prevents the nervous system from putting things into context, and so may cause the amygdala to respond inappropriatley to sensory stimuli, resulting in agression

Question 4

Serotonin

AO1

Answer 4

Typically inhibits the firing of the amygdala. Low levels of serotonin remove this inhibitory effect, so individuals are less able to control impulsive and agressive behaviour. As a reslt, when the amygdala is stimulated by external events, it becomes more active, causing the person to act on their impulses, making agression more likely.

Question 5

Testosterone
Hormonal influences
AO1

Answer 5

The male sex hormone which is thought to influence agression from young adulthood onwards due to its action on areas involved in controlling aggression

Question 6

Testosterone
Sapolsky (1998)
AO1

Answer 6

Described how removing the source of testorenone in different species typically resulting in lower levels of agression. Subsequently reinstating normal testoerne levels with injections synthetic testosyerone led to return of agressive behaviour.

Question 7

Evidence for testosterone-agression link
Dabbs et al. (1987)
AO1

Answer 7

Men are generally more agressive than women (Archer 2009), and have much higher concentrations of testosterone than women. Dabbs et al. (1987) measured salivary testosterone in violent and non-violent criminals, Those with the highest testosterone levels had a history of primarily violent crimes, whereas, those with lowest levels had committed only non-violent crimes.

Question 8

Carre and Olmstead (2015)

AO1

Answer 8

Claim that testosterone concentration are not static, but fluctuate rapidy in the context of changes to the social enviroment. Changes in testosterone levels appear to influence agressive behaviour by increasing amygdala reactivity during the processing of social threat.

Question 9

AO3

Question 10

Evidence for the role of the amygdala in agression
Neural influences
AO3

Answer 10

P: Pardini et al. (2014) found that reduced amygala volume can predict the development of severe and persistent aggression

E: They carried out a longnitudinal study of male p’s from childhood to adulthood. 56% p’s with varying histories of violence had a brain MRI at age 26. Those with lower amygdala volumes exhibited higher level of aggression and violence.

E: This suggests that lower amygdala volume compromises the ability to evalute the emotional importance of sensory information and makes a violent response more likely.

Question 11

Evidence for the role of the hippocampus in aggression.

Answer 11

P: Raine et al. (2004) provided support for the role the hippocampus in agressive behaviour.

E: They studied two groups of violent criminls: one group who had acted impulsively and the others who were ‘cold calculating criminals’. For individuals in the former group, their hippocampus volume in the two hemispheres of the brain differed in size.

E: This asymmetry impairs the ability of the hippocampus and the amygdala to work together, so emotional information is not processed correctly, leading to inapporpriate verbal and physical responses.

Question 12

Inconsistent evidence
Hormonal influences
Abert et al., (1994)
AO3

Answer 12

P: Despite many studies showing a positive relationship between testosterone and aggression, other studies find no relationship

E: Positive correlations have been reported between levels of testosterone and self-reported levels of aggression among prision inmates (Abert et al., 1994). One the other hand, no correlation was found between testosterone levels and actual violent behaviour among male inmates in prision.

E: This suggests that relationship between testosterone and aggression in humans remains unclear.

Question 13

Aggression or dominance
Hormonal influences
AO3

Answer 13

P: Mazur (1985) suggests that we should distinguish between aggression and dominance, and claims that agression is just one form of dominance behaviour.

E: The influence of testosterone on dominance is expressed in varied and subtile ways. Eisenegger et al. (2011) found that testosterone could make act ‘nicer’ rather than more agressively depending on the situation

E: This supports the idea that, rather than directly increasing aggression, testosterone promotes status-seeking behaviour, of which agression is one type.